Ygdir - Use <code>!important</code> for utility classes to make them immutable

S12 Use `!important` for utility classes to make them immutable

For the logic concerning this, I would like to refer to Harry Robert’s “forcing immutability in CSS” logic as explained in this article.

Bad

.u-d-block {
    display: block;
}

Good

.u-d-block {
    display: block !important;
}